v0.5.4

What's Changed

• Checkpoints get a stable content-derived memory uid, an explicit anchor grammar, and a host_session-keyed physical folder layout by @Coder8124 in #59
• Fix 5 code-review findings against the merged A2/C5 memory-format migration by @Coder8124 in #60

Full Changelog: v0.5.3...v0.5.4